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Abstract:

A surgical obturator comprising an elongate shaft extending along an axis
between a proximal end and a distal end includes a bladeless tip disposed
at the distal end of the shaft. The tip has a blunt point and a pair of
shorter side surfaces separated by a relatively longer pair of opposing
surfaces to form in radial cross-section a geometric shape that has a
longer length and relatively narrower width. The side surfaces and
opposing surfaces terminate in end surfaces located proximally from the
blunt point. The end surfaces extend radially outwardly from opposite
locations of the outer surface. A conical surface facilitates initial
insertion of the obturator and the geometric shape facilitates separation
of consecutive layers of muscle tissue having fibers oriented in
different directions and provides proper alignment of the tip between the
layers of muscle.

Claims:

1. A surgical obturator, comprising: an elongate shaft extending along an
axis between a proximal end and a distal end having a blunt point; and a
bladeless tip disposed at the distal end of the shaft having a conical
surface forming proximally into an outer surface, said outer surface
extending distally to a cone with said blunt point and having a pair of
opposing surfaces separated by a pair of side surfaces; wherein the side
surfaces extend from the blunt point radially outwardly with progressive
positions proximally along the axis.

2. The surgical obturator of claim 1 wherein the side surfaces and
opposing surfaces form a geometric shape having a narrow width relative
to a longer length in radial cross-sections of the tip.

3. The surgical obturator of claim 2 wherein the geometric shape is
substantially a rectangle.

4. The surgical obturator of claim 1 wherein the side surfaces are
substantially straight and the opposing surfaces are curved.

5. The surgical obturator of claim 1 wherein the cone intersects with the
opposing surfaces.

6. The surgical obturator of claim 1 wherein the opposing surfaces and
side surfaces terminate distally in a pair of oppositely disposed end
surfaces that extend radially outwardly from opposite sides of the cone.

7. A surgical obturator, comprising: an elongate shaft extending along an
axis between a proximal end and a distal end; and a bladeless tip
disposed at the distal end of the shaft; the tip having an outer surface
forming a blunt end at the distal end of the tip; the outer surface
including a pair of opposing surfaces defining a pair of oppositely
disposed longer sides of a geometric shape in radial cross-sections of
the tip; the opposing surfaces being separated by a pair of side surfaces
defining a pair of oppositely disposed shorter sides of the geometric
shape relative to the longer sides in radial cross-sections of the tip;
wherein the pair of opposing surfaces and pair of side surfaces terminate
distally in a pair of end surfaces that extend radially outwardly at
opposite locations from the outer surface and are located proximally from
the blunt end.

8. The surgical obturator of claim 7 wherein the tip further includes a
conical surface extending proximally from the blunt end.

9. The surgical obturator of claim 8 wherein the end surfaces extend
radially outwardly from the conical surface.

10. The surgical obturator of claim 9 wherein at least a portion of the
conical surface is located between the blunt end and the end surfaces.

11. The surgical obturator of claim 8 wherein at least a portion of the
conical surface extends proximally into the opposing surfaces.

13. The surgical obturator of claim 7 wherein the side surfaces are
substantially straight and the opposing surfaces are curved in radial
cross-sections of the tip.

14. The surgical obturator of claim 7 wherein in consecutively proximal
radial cross-sections the geometric shape appears to rotate in a first
direction about the axis.

15. A surgical obturator adapted to penetrate at least two consecutive
layers of muscle tissue including a first layer of muscle tissue having
fibers oriented in a first direction and a second layer of muscle tissue
having fibers oriented in a second direction, the surgical obturator
comprising: an elongate shaft extending along an axis between a proximal
end and a distal end; and a bladeless tip disposed at the distal end of
the shaft; the tip having an outer surface extending distally to a blunt
end; the outer surface including a pair of opposing surfaces defining a
pair of oppositely disposed longer sides of a geometric shape in radial
cross-sections of the tip; the opposing surfaces being separated by a
pair of side surfaces defining a pair of oppositely disposed shorter
sides of the geometric shape relative to the longer sides in radial
cross-sections of the tip; wherein the outer surface is configured such
that the geometric shape at the distal end of the tip is in a more
parallel alignment with the second direction of orientation of fibers of
the second layer of muscle tissue after penetration of the first layer of
muscle tissue along the first direction of orientation of fibers.

16. The surgical obturator of claim 15 wherein the side surfaces are
substantially straight and the opposing surfaces are curved in radial
cross-sections of the tip.

17. The surgical obturator of claim 15 wherein the geometric shape is
substantially a rectangle.

18. The surgical obturator of claim 15 wherein the outer surface further
includes a conical surface extending distally to the blunt end.

19. The surgical obturator of claim 18 wherein the conical surface is
located between the blunt end and the side surfaces.

20. The surgical obturator of claim 15 wherein the geometric shape is
twisted in one direction along the axis.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent application Ser.
No. 12/836,023 filed on Jul. 14, 2010 which is a continuation of U.S.
patent application Ser. No. 10/514,313, now U.S. Pat. No. 7,758,603,
which entered the U.S. National Phase on Nov. 12, 2004 from International
Application No. PCT/2003/014924, filed May 13, 2003, which published in
English as International Patent Publication WO 2003/096879 A3, which
claims the benefit of U.S. Application No. 60/381,469, filed May 16,
2002. The disclosures of all of these applications are incorporated by
reference in their entireties herein.

[0003] Trocar systems have been of particular advantage in facilitating
less invasive surgery across a body wall and within a body cavity. This
is particularly true in the case of the abdominal surgery where trocars
have provided working channels across the abdominal wall to facilitate
the use of instruments within the abdominal cavity.

[0004] The trocar systems of the past typically include a cannula, which
defines the working channel, and an obturator which is used to place the
cannula across the abdominal wall. The obturator is inserted into the
working channel of the cannula and then pushed through the abdominal wall
with a penetration force of sufficient magnitude to result in penetration
of the abdominal wall. Once the cannula is in place, the obturator can be
removed.

[0005] In the past, obturators have been developed with an intent to
provide a reduction in the force required for penetration. Sharp blades
have typically been used to enable the obturator to cut its way through
the abdominal wall. While the blades have facilitated a reduced
penetration force, they have been of particular concern once the
abdominal wall has been penetrated. Within the abdominal cavity, there
are organs which need to be protected against any puncture by an
obturator.

[0006] In some cases, shields have been provided with the obturators in
order to sense penetration of the abdominal wall and immediately shield
the sharp blades. These shielding systems have been very complex, have
required a large amount of time to deploy, and have generally been
ineffective in protecting the organs against the sharp blades.

[0007] Blunt-tip obturators have been contemplated with both symmetrical
and asymmetrical designs. While the blunt tip tends to inhibit damage to
interior organs, it also tends to increase the penetration force
associated with the obturator. Thus, there is a need in the art for an
improved bladeless obturator that reduces the force required to place the
obturator across the abdominal wall.

SUMMARY

[0008] In accordance with the present invention, a blunt tip obturator
similar to that described in international application No. PCT/US02/06759
further including a cone at its distal tip is disclosed with
characteristics that reduce the force required to penetrate the abdominal
wall. The addition of the cone also reduces the tendency for the
abdominal wall and the peritoneum to deflect or "tent" during insertion
of the obturator. The blunt cone tip obturator of the invention
penetrates and twists radially from a distal end to a proximal end of the
tip. The blunt cone tip obturator facilitates insertion with a reduced
penetration force as the user moves the tip back and forth radially while
applying an axial penetration force. The blunt cone tip obturator can be
directed and inserted between the fibers and then rotated to provide
increased penetration and fiber separation.

[0009] These and other features and advantages of the invention will
become more apparent with a discussion of preferred embodiments in
reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates side views of a trocar system including a
cannula with associated valve housing, and an obturator with a blunt cone
tip extending through the working channel of the cannula to facilitate
placement across the abdominal wall;

[0011]FIG. 2 is a side elevation view of the blunt cone tip of a
preferred embodiment of the invention;

[0012] FIG. 3 is a side elevation view of the blunt cone tip taken along
line 3-3 of FIG. 2;

[0014]FIG. 5 is a radial cross-section view taken along line 5-5 of FIG.
2;

[0015]FIG. 6 is a radial cross-section view taken along line 6-6 of FIG.
2;

[0016]FIG. 7 is a radial cross-section view taken along line 7-7 of FIG.
2;

[0017] FIG. 8 is a radial cross-section view taken along line 8-8 of FIG.
2;

[0018]FIG. 9 is a radial cross-section view taken along line 9-9 of FIG.
2; and

[0019]FIG. 10 is a schematic view illustrating each of the FIGS. 4-9
super-imposed to facilitate an understanding of the blunt cone tip and
its twisted configuration.

DETAILED DESCRIPTION OF THE INVENTION

[0020] A trocar system is illustrated in FIG. 1 and is designated by
reference numeral 10. This system includes a cannula 12, defining a
working channel 14, and a valve housing 16. The system 10 also includes
an obturator 18 having a shaft 21 extending along an axis 23. A handle 25
is disposed at a proximal end of the shaft at 21 while a blunt cone tip
27 is disposed at a distal end of the shaft 21. The shaft 21 of the
obturator 18 is sized and configured for disposition within the working
channel 14 of the cannula 12. With this disposition, the obturator 18 can
be directed to penetrate a body wall such as the abdominal wall to
provide the cannula 12 with access across the wall and into a body
cavity, such as the peritoneal or abdominal cavity. The blunt cone tip 27
serves to direct the obturator 18 through the abdominal wall and the
peritoneum, and can be removed with the obturator 18 once the cannula 12
is operatively disposed with the working channel 14 extending into the
abdominal cavity.

[0021] In order to facilitate penetration of the abdominal wall by the
trocar system 10, a penetration force, represented by an arrow 34, is
typically applied along the axis 23. It can be appreciated that the force
required to penetrate the abdominal wall drops significantly once the
wall is penetrated. Further application of the force 34, even for an
instant of time, can result in injury to organs within the cavity. Where
the obturators of the past have included blades facilitating penetration
of the abdominal wall, these blades have been particularly threatening
and detrimental to the interior organs.

[0022] Consequently, in accordance with the present invention, the tip 27
is provided with a blunt cone configuration. Blunt tips have been used in
the past to reduce any potential for damage to interior organs. However,
these blunt tips have increased the amount of force 34 required for
penetration of the abdominal wall. The blunt cone tip 27 of the present
invention takes into account the anatomical configuration of the
abdominal wall with an improved structural design and method of
insertion.

[0023] To fully appreciate these aspects of this invention, it is helpful
to initially discuss the anatomy associated with the abdominal wall. The
abdominal wall typically includes a skin layer and a series of muscle
layers. The muscle layers are each defined by muscle fibers that extend
generally parallel to each other in a direction that is different for
each of the layers. For example, fibers of a first muscle layer and a
second muscle layer may extend in directions that are 45 degrees off of
each other.

[0024] Having noted the directional nature of the muscle fibers, it can be
appreciated that such a structure is most easily penetrated by an
obturator having a blunt cone tip. The blunt cone tip also has a
rectangular and twisted configuration so as to provide better movement
between the muscle layers. That is, the blunt cone tip is capable of
being moved generally parallel to and between the fibers associated with
a particular muscle layer. As a result, the obturator of the present
invention reduces the penetration force 34 required to push the obturator
18 through a particular layer.

[0025] As described earlier, the fibers of the muscle layers may be
oriented at different angles to each other such that proper alignment of
the tip 27 for penetration of one layer may not necessarily result in
proper alignment for penetration of the next layer. For at least this
reason, the obturator 18 has a blunt cone tip 27 to direct the obturator
18 through the different layers and a rectangular configuration that is
twisted slightly so that penetration of a first layer begins to rotate
the distal end of the blunt cone tip 27 into proper orientation for
penetration of the next layer.

[0026] The twisted configuration of the blunt cone tip 27 also causes the
blunt cone tip 27 to function with the mechanical advantage of a screw
thread. With this configuration, a preferred method of placement requires
that the user grip the handle 25 of the obturator 18 and twist it about
the axis 23. This twisting motion in combination with the screw
configuration of the blunt cone tip 27 converts radial movement into
forward movement along the axis 23. Thus, the user applies both a
forwardly directed force as well as a radial force to move the trocar
system 10 in a forward direction. Since all of the force supplied by the
user is not directed axially along the arrow 34, this concept avoids the
tendency of prior trocar systems to jump forward upon penetration of the
abdominal wall.

[0027] The twisted configuration of the blunt cone tip 27 is most apparent
in the side elevation views of FIGS. 2 and 3. In this embodiment, the
blunt cone tip 27 comprises generally of eight surfaces: two opposing
surfaces 50 and 52, separated by two side surfaces 54 and 56, two end
surfaces 58 and 59, a conical surface 60 formed in surfaces 50 and 52
around axis 23 and extending beyond end surfaces 58 and 59, and a blunt
surface 62. A plane drawn through the axis 23 would show the tip 27 to be
composed of two symmetrical halves.

[0028] The surfaces 50 and 52, side surfaces 54 and 56, and conical
surface 60 generally define the cross section of the blunt cone tip 27
from blunt surface 62 to proximal end 61. This configuration can best be
appreciated with reference to the cross section views of FIGS. 4-9. In
FIG. 4, the distal end of the blunt cone tip 27 is shown with a circle 64
having the smallest circular area and a rectangle 63 having the greatest
length-to-width ratio. The rectangle 63 has a twisted, S-shaped
configuration at end surfaces 58 and 59.

[0029] As views are taken along progressive proximal cross sections, it
can be seen that the circle 64 becomes larger and the rectangle 63
becomes less twisted, and the width increases relative to the length of
the rectangle 63. The spiral nature of the blunt cone tip 27 is also
apparent as the circle 64 and rectangle 63 move counterclockwise around
the axis 23. This is perhaps best appreciated in a comparison of the
circle 64 and the rectangle 63 in FIG. 6 relative to that in FIG. 5. With
progressive proximal positions, the circle 64 begins to expand with
increasing circular area and the rectangle 63 begins to widen with a
reduction in the ratio of length to width. The long sides of the
rectangle 63 also tend to become more arcuate as they approach a more
rounded configuration most apparent in FIGS. 8 and 9. That is, the circle
64 and the rounded rectangle 63 become more concentric with progressive
proximal positions. Furthermore, the circle 64 expands at a lesser rate
than the rectangle 63, which eventually absorbs the circle 64 as shown in
FIGS. 8 and 9. In these figures, it will also be apparent that the
rotation of the rectangle 63 reaches a most counterclockwise position and
then begins to move clockwise. This is best illustrated in FIGS. 7-9.
This back and forth rotation results from the configuration of the side
surfaces 54 and 56, which in general are U-shaped as best illustrated in
FIGS. 2 and 3.

[0030] The ratio of the length to width of the rectangle 63 is dependent
on the configuration of the side surfaces 54 and 56, which define the
short sides of the rectangle 63 as well as the configuration of the
surfaces 50 and 52, which define the long sides of the rectangle 63.
Again with reference to FIGS. 2 and 3, it can be seen that the side
surfaces 54 and 56 are most narrow at the end surfaces 58 and 59. As the
side surfaces 54 and 56 extend proximally, they reach a maximum width
near the point of the most counterclockwise rotation, shown generally in
FIG. 8, and then reduce in width as they approach the proximal end 61.
Along this same distal to proximal path, the surfaces 50 and 52
transition from a generally flat configuration at the end surfaces 58 and
59 to a generally rounded configuration at the proximal end 61.

[0031] In the progressive views of FIGS. 5-7, the circle 64 is further
designated with a lower case letter a, b or c, respectively; similarly,
the rectangle 63 is further designated with a lower case letter a, b, c,
d or e, respectively, in FIGS. 5-9. In FIG. 10, the circles 64, 64a-64c
and the rectangles 63, 63a-63e are superimposed on the axis 23 to show
their relative sizes, shapes and angular orientations.

[0032] A preferred method of operating the trocar system 10 benefits
significantly from this preferred shape of the blunt cone tip 27. With a
conical configuration at the distal point and a rectangular configuration
at a distal portion of the tip, the tip 27 appears much like a flathead
screwdriver having a cone at its tip. Specifically, the blunt tip
includes a conical structure extending outward from the end surfaces 58
and 59 that serves to direct the obturator through the abdominal wall and
peritoneum. The cone tip has a radius of approximately 0.025''. The
incorporation of the cone onto the rectangular configuration reduces the
insertion force required to traverse the abdominal wall. An advantage of
the obturator of the invention is it provides a safer and more controlled
entry of the abdominal cavity.

[0033] It is preferable that the lengths of the end surfaces 58 and 59 are
aligned parallel with the fibers of each muscle layer. With this shape,
the blunt cone tip can be used to locate or pinpoint a desired location
and penetrate the abdominal wall. A simple back and forth twisting motion
of the blunt cone tip tends to separate the fibers along natural lines of
separation, opening the muscle layer to accept the larger diameter of the
cannula 12. By the time the first layer is substantially penetrated, the
conical and twisted configuration of the blunt cone tip 27 directs and
turns the rectangle 63 more into a parallel alignment with fibers in the
next layer. Again, the blunt cone tip facilitates penetration, and the
twisting or dithering motion facilitates an easy separation of the fibers
requiring a significantly reduced penetration and insertion force along
the arrow 34.

[0034] It should be further noted that the blunt cone tip 27 is bladeless
and atraumatic to organs and bowel within the peritoneal or abdominal
cavity. The blunt cone tip 27 also minimizes tenting of the peritoneum
and allows for a safe entry. The device is typically used in conjunction
with the cannula 12 to create an initial entryway into the peritoneal
cavity. The obturator 18 is first inserted through the valve housing 16
and into the cannula 12. The entire trocar system 10 is then inserted
through the abdominal wall and into the peritoneal cavity. Once the
cannula 12 is properly placed, the obturator 18 can be removed.

[0035] The invention facilitates a unique method of penetrating and
separating tissue and could apply to any object with a blunt cone tip and
generally flat sides. When inserted into the peritoneum the blunt cone
tip requires very little area to move safely between tissue and muscle
fibers. The device can then be rotated in alternating clockwise and
counterclockwise directions while the downward penetration force is
applied. When rotated in alternating directions, the tissue is moved
apart and a larger opening is created for a profile of greater cross
sectional area to follow. This process continues with safety as the
device enters the peritoneal cavity and moves to its operative position.

[0036] When the cannula 12 is ultimately removed, the size of the opening
left in the tissue is minimal. Importantly, this opening is left sealed
due to a dilating effect caused by the mere separation of fibers. Since
there are no blades or sharp edges to cut muscle fiber, the healing
process is significantly shortened.

[0037] The obturator 18 can be constructed as a single component or
divided into multiple components such as the shaft 21 and the blunt cone
tip 27. If the obturator 18 is constructed as a single component, it may
be constructed of either disposable or reusable materials. If the
obturator 18 is constructed as two or more components, each component can
be made either disposable or reusable as desired for a particular
configuration. In a preferred embodiment, the obturator is constructed as
a single component made from a reusable material such as metal (e.g.,
stainless steel) or an autoclavable polymer to facilitate
re-sterilization.

[0038] In another embodiment of the invention, the blunt cone tip 27 can
be coated or otherwise constructed from a soft elastomeric material. In
such a case, the material could be a solid elastomer or composite
elastomer/polymer.

[0039] The shaft 21 of the obturator 18 could be partially or fully
flexible. With this configuration, the obturator 18 could be inserted
through a passageway containing one or more curves of virtually any
shape. A partially or fully flexed obturator 18 could then be used with a
flexible cannula 12 allowing greater access to an associated body cavity.

[0040] The obturator 18 could also be used as an insufflation needle and
provided with a passageway and valve to administer carbon dioxide or
other insufflation gas to the peritoneal cavity. The obturator 18 could
also be used with an insufflation needle cannula, in which case removal
of the obturator 18 upon entry would allow for rapid insufflation of the
peritoneal cavity.

[0041] It will be understood that many modifications can be made to the
disclosed embodiments without departing from the spirit and scope of the
invention. For example, various sizes of the surgical device are
contemplated as well as various types of constructions and materials. It
will also be apparent that many modifications can be made to the
configuration of parts as well as their interaction. For these reasons,
the above description should not be construed as limiting the invention,
but should be interpreted as merely exemplary of preferred embodiments.